diff --git a/smtp.scm b/smtp.scm
index 917a06d..22e7bf1 100644
--- a/smtp.scm
+++ b/smtp.scm
@@ -71,9 +71,9 @@
 			     (lambda (to)
 			       (receive (code text) (smtp/rcpt socket to)
 				 (and (>= code 400) ; Error
-				      (? ((>= 600)
-					  (smtp/quit socket)
-					  (bailout code text))
+				      (cond ((>= code 600)
+					     (smtp/quit socket)
+					     (bailout code text))
 					 (else `(,to ,code ,@text))))))
 			     to-list)))